Fat added to poultry and swine feeds often contains abundant free fatty acids (FFA) that can impair digestible energy (DE). Placement of the fatty acid (FA) hydrocarbon chain in the helix core reformed from amylose creates a complex of both nutrients. Resulting modifications create a new structure termed the V-helix that becomes resistant to α-amylase. Granules in grain naturally contain minimal amounts of these complexes with more being generated during food manufacturing when moisture and heat release amylose in the presence of FFA. A paucity of FFA usually exists in complete feeds without sources of poor-quality fat. Animal fats and by-product meals from rendering are prominent in their saturated FFA content which favorably complex within the helix. V-helix-FA complexes may arise during their concurrent encounter of FFA together with amylose during feed manufacture, particularly pelleting. FFA in the gastrointestinal tract (GIT) are speculated to further form complexes when present together with amylose. Although amylose may be dissolved in the gastric and small intestinal milieu, FFA separately coalesce into hydrophobic fat droplets along with other dietary lipids. Formation of complexes is likely restricted until FFA are released into the aqueous phase during fat digestion. Although α-amylase may be prominent, V-helix-FA complexes being resistant to enzymic attack pass into the large intestine. Subsequent microbial catabolism of V-helices may generate volatile fatty acids that are absorbed by the mucosa; however, an inability to use FFA once released leads to their excretion and basis for decreased DE. Immature microbial populations with young animals usually lack the capacity to fully catabolize the V-helix, further extending the loss in DE.

添加到家禽和猪饲料中的脂肪通常含有丰富的游离脂肪酸 (FFA)，会损害可消化能量 (DE)。将脂肪酸 (FA) 碳氢链放置在由直链淀粉改造而成的螺旋核心中，形成了两种营养素的复合物。由此产生的修饰产生了一种称为 V 螺旋的新结构，该结构对 α-淀粉酶具有抗性。谷物中的颗粒天然含有极少量的这些复合物，而在食品制造过程中，当水分和热量在 FFA 存在下释放直链淀粉时，会产生更多的复合物。不含劣质脂肪来源的全价饲料中通常存在少量 FFA。动物脂肪和提炼副产品粉的饱和 FFA 含量突出，有利于在螺旋内形成复合物。在饲料生产过程中，特别是制粒过程中，FFA 与直链淀粉同时相遇时，可能会产生 V 螺旋-FA 复合物。据推测，胃肠道 (GIT) 中的 FFA 与直链淀粉一起存在时会进一步形成复合物。尽管直链淀粉可能溶解在胃和小肠环境中，但 FFA 会与其他膳食脂质一起单独聚结成疏水性脂肪滴。在脂肪消化过程中 FFA 释放到水相中之前，复合物的形成可能会受到限制。尽管 α-淀粉酶可能很重要，但能够抵抗酶攻击的 V-螺旋-FA 复合物会进入大肠。V 螺旋随后的微生物分解代谢可能会产生挥发性脂肪酸，并被粘膜吸收；然而，FFA 一旦释放就无法使用，导致它们被排泄并成为 DE 降低的基础。幼龄动物的未成熟微生物群体通常缺乏完全分解代谢 V 螺旋的能力，进一步延长了 DE 的损失。